Description
Size: 16 mm long by 8 mm wide; the length of the foot is 15.5 mm and the height 4.5 mm.

Color: Brown, almost chestnut rhinophores and branchiae, and a line of red dots along the margin of the mantle and some red spots on the tail. On the dorsum there are numerous, almost circular purple-black spots and a few similar spots on the tail, and the margin of the mantle has a white band around it. The branchiae have numerous, tiny, opaque white spots scattered all over them.

The body is with a wide, outstanding plate-like dorsum held well above the body. The dorsum is oval, but slightly broader in front than behind. The body is narrower than the dorsum and its sides are upright; its posterior end is carried on into a thin, pointed tail, quite independent of the dorsum. The head is very small and hidden between the overhanging mantle above and the anterior margin of the foot below; it is continued laterally into small oral tentacles. The foot is muscular but much narrower than the mantle. It is nearly as long as the dorsum, but since it starts a short distance from the front end of the latter and this also possesses a wide posterior flange-like margin, the foot passes over into a noticeable tail. The branchiae are ten in number, the two posterior ones being the smallest, and they are arranged in a circle which is not quite closed behind. The anus lies on a low papilla within the circle of the branchiae.
The buccal mass is well developed and the lips are covered with a very thin disc of chitin, which towards the mouth opening becomes thicker and turns in over the T-shaped mouth aperture to form a lining for the first part of the buccal tube. The thin part of the disc is smooth, the thicker part is beset with numerous, closely packed, curved denticles, which are bifid in the outer region but in the thickest rim around the mouth they are simple, still curved, longer and more closely packed. The radula is long and narrow and comes to a sharp point. It contains 74 rows of teeth, of which the last four or five are incompletely formed: there is no rhachidial tooth.
The formula of the first row is 2.0.0; of the second 8.0.8; of the third 15.0.13; of the fifth 19.0-17; and of a fully formed row 46-44.0.44-46. The teeth of the first six or seven rows are much worn. The inner tooth has roughly rectangular base with a short, pointed blade, flanked on the median side by a smaller blade and bearing on the outer side two denticulations. The second tooth has a pointed thorn-like blade, bearing on its outer face about the middle three denticulations. As the teeth pass outwards the blade becomes larger and the denticulations increase in number from three to six and also migrate downwards on to the inner curve of the blade, so that the blade becomes comb-like. The teeth reach their maximum size about half-way out. Near the outside the blade becomes wider and the denticulations lie right on the margin. The outermost tooth shows the number of denticulations reduced to four and the point shortened, so that the denticulations and the point lie in a line almost at right angles to those of the other teeth.

Synonym (s)

Common Name (s)

Economic Importance and Threats

Ecology

Biogeography

• Tamil Nadu, Pamban INDIA

Literature Source(s)

O'Donoghue, CH (1932) Notes on Nudibranchiata from southern India Journal of Molluscan Studies The Malacological Society of London 20(3) 141-166 Available at - http://mollus.oxfordjournals.org/content/20/3/141.full.pdf+html

Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org